with a brake of the aforementioned type, the brake disk is generally located on the shaft of an engine or motor. The non-rotary armature plate is raisable from the brake disk by the electromagnet, so that the brake disk can then freely rotate with the motor. For braking purposes the electromagnet is deexcited or deenergized, so that the armature plate connected in non-rotary manner to a casing, under the action of helical springs inserted in the magnet body, is pressed for braking purposes against the brake disk. Generally brake linings are provided on the brake disk for improving the braking action. Optionally the brake disk can also be pressed by the armature plate against a casing-fixed bearing surface.
On energizing or de-energization the electromagnet, the armature plate strikes at a relatively high speed against the pole face of the magnet body or on the brake disk, which leads to considerable impact noise. This is more particularly the case with rapidly operating and pulse-magnetized brakes, in which the impact noise occurs to a greater extent as a result of the increased speeds.
Attempts have already been made to reduce the impact noise by making the armature from stacked sheets (DE-OS 22 59 320). In addition, in DE-OS 28 40 565, for reducing the impact noise there are cup springs on the magnet body for decelerating the armature plate. It must be borne in mind that the stacked sheets have a greatly reduced stability as compared with a solid armature plate. In addition, the noise reducing effect through cup springs is limited with stacked sheets and negligible with solid armature plates, so that these solutions are in fact disadvantageous in the case of pulse-magnetized brakes which, as a result of the high speed and forces, require a very stable armature plate.
It is known from German Utility model 89 13 767 to form the armature plate in the case of such a brake from individual metal disks between which is, in each case, arranged a damping material layer. For the same dimensions as a solid armature plate, this construction leads to a significant stability decrease. However, if a stability equivalent to that of a solid armature plate is to be achieved, much greater dimensions are required, which has a disadvantageous effect with rapidly operating brakes.